Sponsored Content
Top Forums Shell Programming and Scripting multiple conditions in if statements Post 20513 by Jimbo on Sunday 28th of April 2002 09:42:39 AM
Old 04-28-2002
On assignments to a variable, do x= instead of $x= .

When you use a mixture of -o and -a, you might have to control precedence. In the following, the first line would test true because -o has precedence:
if [ a = a -o b = b -a c = C ]
But add parentheses (you would need to backslash these) and it would now test false:
if [ ( a = a -o b = b ) -a c = C ]

Also, when checking for several values, a case statement makes for nice clean code, and even more handy when each value will result in a different action:
case $x in
 +|-|/|%) x=$vr1;;
       *) print "You have entered an invalid option."
          exit 1;;


10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

multiple 'if' statements out of array

I want to do multiple comparisons on a series of numbers from an array: I send the numbers in file1 through want to print out some info from file2 based on some conditions. The syntax just isn't correct??? awk ' NR==FNR{ a=$0 next ... (2 Replies)
Discussion started by: dcfargo
2 Replies

2. Shell Programming and Scripting

if then statements with two conditions...?

Is it possible to setup two conditions for an if then statement in a pbash script? For example, depending on the text value of a variable I parse out of an xml file, I want to assign it a numerical values. Example: if ; then VAR="25" fi if ; then VAR="25" fi Can these two... (3 Replies)
Discussion started by: audiophile
3 Replies

3. Shell Programming and Scripting

Help regarding multiple conditions

Hi All, I am new to shell scripting. Can any one say what is wrong in this if statement, that uses multiple conditions if then *************** else if ( -z $pcs && "$night_time_calc" > "$night_time" ) then ******************************** ... (4 Replies)
Discussion started by: ssenthilkumar
4 Replies

4. Shell Programming and Scripting

How do I execute multiple statements within If then else

Please help me. I have been doing this for several hours. Here is the code if then echo a b c d >> file.txt echo 1111 >> file.txt fi The reason I want the two echo is because I want these statements printed on multiple lines. I keep getting error . First it tells me... (2 Replies)
Discussion started by: asemota
2 Replies

5. Shell Programming and Scripting

Running multiple if statements

Hi, Hav automated a process, and it is working fine. for first process alone status = ` ps -ef |grep a ` if then echo " Success" > temp/logfile else echo " Failure" > temp/logfile fi Now I hav to write script to automated some 2 process and then send mail using cron.. ... (5 Replies)
Discussion started by: NehaKrish
5 Replies

6. Shell Programming and Scripting

execute multiple statements in if-else

how can we execute multiple statements in else condition i have if then statement else statements fi in else condition i have multiple statements but it executing only one statement is there any way to execute multiple statements (4 Replies)
Discussion started by: nani1984
4 Replies

7. Shell Programming and Scripting

Multiple if Statements

Hi All, I need to check for 3 conditions and if all the 3 are not satified need to say that services are not running.... is the below code correct. #********** Check to see if Service 1 is still running************** if then echo "$datetimestamp: Service1 is not running" >>... (4 Replies)
Discussion started by: ch33ry
4 Replies

8. Shell Programming and Scripting

Multiple while statements?

I'm working on a script for class as a final project. We have to ask for values (city, state, zip) five times, but the state can only be MI, IN, IL, or OH. I'm trying to do this with a while loop inside of a while loop, but I have no idea how to do it properly. Here's what I have so far: ... (3 Replies)
Discussion started by: nickzourdos
3 Replies

9. UNIX for Dummies Questions & Answers

Multiple if statements

exmaple: file1 and file2 has 1 bit if then exit else send out email fi if then exit else send out email fi it exits the 1st if. did not continue with my 2nd if. thanks in advanced. Please use CODE tags are suggested on every page when you post an item in... (7 Replies)
Discussion started by: lawsongeek
7 Replies

10. Shell Programming and Scripting

Using multiple 'for' statements

Hello, I am new to scripting and I am trying to write a simple script that creates users and adds their passwords from two files; one a user list file and another a password list file. For example, I have two files already. $ cat file1 andy stephane aby paul $ cat file2 123 234... (4 Replies)
Discussion started by: FemoTheDon
4 Replies
EXPR(1) 						      General Commands Manual							   EXPR(1)

expr - evaluate arguments as an expression SYNOPSIS
expr arg ... DESCRIPTION
The arguments are taken as an expression. After evaluation, the result is written on the standard output. Each token of the expression is a separate argument. The operators and keywords are listed below. The list is in order of increasing precedence, with equal precedence operators grouped. expr | expr yields the first expr if it is neither null nor `0', otherwise yields the second expr. expr & expr yields the first expr if neither expr is null or `0', otherwise yields `0'. expr relop expr where relop is one of < <= = != >= >, yields `1' if the indicated comparison is true, `0' if false. The comparison is numeric if both expr are integers, otherwise lexicographic. expr + expr expr - expr addition or subtraction of the arguments. expr * expr expr / expr expr % expr multiplication, division, or remainder of the arguments. expr : expr The matching operator compares the string first argument with the regular expression second argument; regular expression syntax is the same as that of ed(1). The (...) pattern symbols can be used to select a portion of the first argument. Otherwise, the matching operator yields the number of characters matched (`0' on failure). ( expr ) parentheses for grouping. Examples: To add 1 to the Shell variable a: a=`expr $a + 1` To find the filename part (least significant part) of the pathname stored in variable a, which may or may not contain `/': expr $a : '.*/(.*)' '|' $a Note the quoted Shell metacharacters. SEE ALSO
ed(1), sh(1), test(1) DIAGNOSTICS
Expr returns the following exit codes: 0 if the expression is neither null nor `0', 1 if the expression is null or `0', 2 for invalid expressions. EXPR(1)

Featured Tech Videos

All times are GMT -4. The time now is 11:52 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy